1. Field of the Invention
The present invention relates to an instrument used together with an endoscope in a surgical operation using the endoscope.
2. Description of the Related Art
In a surgical operation using an endoscope, treatment tools such as forceps are used. An example of the treatment tool is disclosed in U.S. Pat. No. 6,245,085. In an operation using such a treatment tool, a hole (called a “port”) having a diameter of 5 to 10 mm is provided in a body wall, and the treatment tool is inserted through the hole. In this case, the area where treatment is possible is narrower in comparison with an open operation in which a portion of a body wall is cut and opened. Therefore, when an area to be treated is large or the position of the hole is inappropriate with respect to the part to be treated, the operation of the treatment tool may be difficult, or the treatment may be complicated. In such a case, if another hole is provided at another position, the damaged area in the patient's body is increased in size.
PCT International Publication, No. WO98/48687 discloses a treatment tool for solving the above problems. In the disclosed treatment tool, a treatment section and an operation section are not coaxially arranged. When using such a treatment tool, it is difficult for the operator to intuitively know the position to be treated. Additionally, a possible amount of offset between the treatment section and an inserted portion is restricted depending on the outer diameter of the hole provided in a body wall. In order to secure a sufficiently wide area which can be treated, the diameter of the hole must be large. Therefore, it is difficult to perform wide area treatment with low damage.